PCR analyses of FhbB and its flanking regions in diverse T. denticola strains. Regions internal to or flanking fhbB were PCR amplified from T. denticola strains 35405, 33520, and GM-1. Control reactions were performed with no DNA template added (Neg.) (A). The primers used are indicated above the lanes. The primer numbers correspond to the following primers: primer 1, FhbB Up; primer 2, TDE0108FLIC; primer 3, FhbB78R; primer 4, TDE0108RLIC; primer 5, TDE0109R1; and primer 6, TDE0109R2. All primer sequences are shown in Table 2. The target sites for the primers are indicated in panel B.